Dave Clark G4C flight suits were designed for wear by Gemini astronauts. Spacesuit designers followed the U.S. Air Force approach toward greater suit mobility when they began to develop the spacesuit for the two-man Gemini spacecraft. The suit was used for the first American spacewalk on Gemini 4, and on all subsequent flights except the Gemini 7 long-duration mission.

Instead of the fabric-type joints used in the Mercury suit, the Gemini spacesuit had a combination of a pressure bladder and a link-net restraint layer that made the whole suit flexible when pressurized. The gas-tight, man-shaped pressure bladder was made of Neoprene-coated nylon and covered by load-bearing link-net woven from Dacron and Teflon cords. The net layer, being slightly smaller than the pressure bladder, reduced the stiffness of the suit when pressurized and served as a sort of structural shell, much like a tire contained the pressure load of the inner tube in the era before tubeless tires, Improved arm and shoulder mobility resulted from the multi-layer design of the Gemini suit.

Specification

G4C Chronology

10 May 1962 Gemini Project Office directed McDonnell to determine what would be involved in opening and closing the spacecraft hatches in the space environment.

Manned Spacecraft Center's Life Systems Division to determine what special pressure suit features would be required to provide crew members with a 15-minute extravehicular capability.

These included evaluation of a superinsulation coverall, worn over the pressure suit, for thermal protection; ventilation system requirements and hardware; and methods of maneuvering in proximity to the spacecraft.

17 October 1964 First Gemini extravehicular prototype suit.

Crew Systems Division reported that the first Gemini extravehicular prototype suit had been received from the contractor and assigned to Astronaut James A.McDivitt for evaluation in the Gemini mission simulator. Crew Systems Division reported that the first Gemini extravehicular prototype suit had been received from the contractor and assigned to Astronaut James A. McDivitt for evaluation in the Gemini mission simulator. During the test, McDivitt complained of some bulkiness and immobility while the suit was in the unpressurized condition, but the bulk did not appear to hinder mobility when the suit was pressurized. The thermal/micrometeoroid cover layer had been installed on a test suit sent to Ling-Temco-Vought for thermal testing in the space simulator chamber.

This suit contained a thermal/micrometeoroid cover layer, a redundant closure, and the open visor assembly for visual, thermal, and structural protection. Zero-gravity tests in January 1965 showed the suit to be generally satisfactory, but the heavy cover layer made moving around in it awkward. The cover layer was redesigned to remove excess bulk. The new cover layer proved satisfactory when it was tested in February.

29 March 1965 Full EVA considered for Gemini 4. Launch Vehicle: Titan 2.

The possibility of doing more than the previously planned stand-up form of extravehicular activity (EVA) was introduced at an informal meeting in the office of Director Robert R. Gilruth at Manned Spacecraft Center (MSC). Present at the meeting, in addition to Gilruth and Deputy Director George M. Low, were Richard S. Johnston of Crew Systems Division (CSD) and Warren J. North of Flight Crew Operations Division. Johnston presented a mock-up of an EVA chestpack, as well as a prototype hand-held maneuvering unit. North expressed his division's confidence that an umbilical EVA could be successfully achieved on the Gemini-Titan 4 mission. Receiving a go-ahead from Gilruth, CSD briefed George E. Mueller, Associate Administrator for Mannned Space Flight, on April 3 in Washington. He, in turn, briefed the Headquarters Directorates. The relevant MSC divisions were given tentative approval to continue the preparations and training required for the operation. Associate Administrator of NASA, Robert C. Seamans, Jr., visited MSC for further briefing on May 14. The enthusiasm he carried back to Washington regarding flight-readiness soon prompted final Headquarters approval.

15 May 1965 Qualification of the G4C extravehicular suit was completed.

This suit was basically the same as the G3C suit except for modifications which included a redundant zipper closure, two over-visors for visual and physical protection, automatic locking ventilation settings, and a heavier cover layer incorporating thermal and micrometeoroid protection. Six G4C suits would be at the launch site for the Gemini 4 flight crews by the end of May.

19 May 1965 All extravehicular equipment planned for the Gemini 4 mission qualified.

All extravehicular equipment planned for the Gemini 4 mission, including the ventilation control module, the extravehicular umbilical assembly, and the hand-held maneuvering unit, had been qualified. The flight hardware was at the launch site ready for flight at the end of May.